<script>
import {
  closest, getOffset, getPrecedingRange,
  getRange, applyRange,
  scrollIntoView, getAtAndIndex
} from '../js/util'
import AtTemplate from './AtTemplate.vue'
export default {
  name: 'At',
  mixins: [AtTemplate],
  props: {
    value: {
      type: String, // value not required
      default: null
    },
    at: {
      type: String,
      default: null
    },
    ats: {
      type: Array,
      default: () => ['@']
    },
    suffix: {
      type: String,
      default: ' '
    },
    loop: {
      type: Boolean,
      default: true
    },
    allowSpaces: {
      type: Boolean,
      default: true
    },
    tabSelect: {
      type: Boolean,
      default: false
    },
    hoverSelect: {
      type: Boolean,
      default: true
    },
    members: {
      type: Array,
      default: () => []
    },
    nameKey: {
      type: String,
      default: ''
    },
    filterMatch: {
      type: Function,
      default: (name, chunk) => {
        // match at lower-case
        return name.toLowerCase()
          .indexOf(chunk.toLowerCase()) > -1
      }
    },
    deleteMatch: {
      type: Function,
      default: (name, chunk, suffix) => {
        return chunk === name + suffix
      }
    },
    scrollRef: {
      type: String,
      default: ''
    },
    isBlur: {
      type: Boolean,
      default: true
    }
  },

  data () {
    return {
      // at[v-model] mode should be on only when
      // initial :value/v-model is present (not nil)
      bindsValue: this.value != null,
      customsEmbedded: false,
      hasComposition: false,
      atwho: null
    }
  },
  computed: {
    atItems () {
      return this.at ? [this.at] : this.ats
    },
    currentItem () {
      if (this.atwho) {
        return this.atwho.list[this.atwho.cur]
      }
      return ''
    },
    style () {
      if (this.atwho) {
        // eslint-disable-next-line no-unused-vars
        const { list, cur, x, y } = this.atwho
        const { wrap } = this.$refs
        if (wrap) {
          const offset = getOffset(wrap)
          const scrollLeft = this.scrollRef ? document.querySelector(this.scrollRef).scrollLeft : 0
          const scrollTop = this.scrollRef ? document.querySelector(this.scrollRef).scrollTop : 0
          const left = x + scrollLeft + window.pageXOffset - offset.left + 'px'
          const top = y + scrollTop + window.pageYOffset - offset.top + 'px'
          return { left, top }
        }
      }
      return null
    }
  },
  watch: {
    'atwho.cur' (index) {
      if (index != null) { // cur index exists
        this.$nextTick(() => {
          this.scrollToCur()
        })
      }
    },
    members () {
      this.handleInput(true)
    },
    value (value) {
      if (this.bindsValue) {
        this.handleValueUpdate(value)
      }
    },
    atwho (val) {
      this.$emit('memberHover', val)
    }
  },
  mounted () {
    if (this.$scopedSlots.embeddedItem) {
      this.customsEmbedded = true
    }
    if (this.bindsValue) {
      this.handleValueUpdate(this.value)
    }
  },
  methods: {
    itemName (v) {
      const { nameKey } = this
      return nameKey ? v[nameKey] : v
    },
    isCur (index) {
      return index === this.atwho.cur
    },
    handleValueUpdate (value) {
      const el = this.$el.querySelector('#myEditor')
      if (value !== el.innerHTML) { // avoid range reset
        el.innerHTML = value
      }
    },

    handleItemHover (e) {
      if (this.hoverSelect) {
        this.selectByMouse(e)
      }
    },
    handleItemClick (e) {
      this.selectByMouse(e)
      this.insertItem()
    },
    handleDelete (e) {
      const range = getPrecedingRange()
      if (range) {
        // fixme: Very bad code from me
        if (this.customsEmbedded && range.endOffset >= 1) {
          let a = range.endContainer.childNodes[range.endOffset] ||
            range.endContainer.childNodes[range.endOffset - 1]
          // eslint-disable-next-line no-mixed-operators
          if (!a || a.nodeType === Node.TEXT_NODE && !/^\s?$/.test(a.data)) {
            return
          } else if (a.nodeType === Node.TEXT_NODE) {
            if (a.previousSibling) a = a.previousSibling
          } else {
            if (a.previousElementSibling) a = a.previousElementSibling
          }
          let ch = [].slice.call(a.childNodes)
          ch = [].reverse.call(ch)
          ch.unshift(a)
          let last;
          [].some.call(ch, c => {
            if (c.getAttribute && c.getAttribute('data-at-embedded') != null) {
              last = c
              return true
            }
          })
          if (last) {
            e.preventDefault()
            e.stopPropagation()
            const r = getRange()
            if (r) {
              r.setStartBefore(last)
              r.deleteContents()
              applyRange(r)
              this.handleInput()
            }
          }
          return
        }

        const { atItems, members, suffix, deleteMatch, itemName } = this
        const text = range.toString()
        const { at, index } = getAtAndIndex(text, atItems)

        if (index > -1) {
          const chunk = text.slice(index + at.length)
          const has = members.some(v => {
            const name = itemName(v)
            return deleteMatch(name, chunk, suffix)
          })
          if (has) {
            e.preventDefault()
            e.stopPropagation()
            const r = getRange()
            if (r) {
              r.setStart(r.endContainer, index)
              r.deleteContents()
              applyRange(r)
              this.handleInput()
            }
          }
        }
      }
    },
    handleKeyDown (e) {
      const { atwho } = this
      if (atwho) {
        if (e.keyCode === 38 || e.keyCode === 40) { // ↑/↓
          if (!(e.metaKey || e.ctrlKey)) {
            e.preventDefault()
            e.stopPropagation()
            this.selectByKeyboard(e)
          }
          return
        }
        if (e.keyCode === 13 || (this.tabSelect && e.keyCode === 9)) { // enter or tab
          this.insertItem()
          e.preventDefault()
          e.stopPropagation()
          return
        }
        if (e.keyCode === 27) { // esc
          this.closePanel()
          return
        }
      }
      if (e.keyCode === 8) {
        // this.handleDelete(e)
      }
    },
    // compositionStart -> input -> compositionEnd
    handleCompositionStart () {
      this.hasComposition = true
    },
    handleCompositionEnd () {
      this.hasComposition = false
      this.handleInput()
    },
    handleInput (keep) {
      if (this.hasComposition) return
      const el = this.$el.querySelector('#preId')
      this.$emit('input', el.innerHTML)
      const range = getPrecedingRange()
      if (range) {
        const { atItems, allowSpaces } = this
        let show = true
        const text = range.toString()
        const { at, index } = getAtAndIndex(text, atItems)
        if (index < 0) show = false
        const chunk = text.slice(index + at.length, text.length)
        if (!allowSpaces && /\s/.test(chunk)) {
          show = false
        }
        // chunk以空白字符开头不匹配 避免`@ `也匹配
        if (/^\s/.test(chunk)) show = false
        if (!show) {
          this.closePanel()
        } else {
          const { members, filterMatch, itemName } = this
          if (!keep && chunk) { // fixme: should be consistent with AtTextarea.vue
            this.$emit('at', chunk)
          }
          const matched = members.filter(v => {
            const name = itemName(v)
            return filterMatch(name, chunk, at)
          })
          if (matched.length) {
            this.openPanel(matched, range, index, at)
          } else {
            this.closePanel()
          }
        }
      }
    },
    closePanel () {
      if (this.atwho) {
        this.atwho = null
      }
    },
    openPanel (list, range, offset, at) {
      const fn = () => {
        const r = range.cloneRange()
        r.setStart(r.endContainer, offset + at.length) // 从@后第一位开始
        // todo: 根据窗口空间 判断向上或是向下展开
        const rect = r.getClientRects()[0]
        this.atwho = {
          range,
          offset,
          list,
          x: rect.left,
          y: rect.top,
          cur: 0 // todo: 尽可能记录
        }
      }
      if (this.atwho) {
        fn()
      } else { // 焦点超出了显示区域 需要提供延时以移动指针 再计算位置
        setTimeout(fn, 10)
      }
    },
    scrollToCur () {
      const curEl = this.$refs.cur[0]
      const scrollParent = curEl.parentElement.parentElement // .atwho-view
      scrollIntoView(curEl, scrollParent)
    },
    selectByMouse (e) {
      const el = closest(e.target, d => {
        return d.getAttribute('data-index')
      })
      const cur = +el.getAttribute('data-index')
      this.atwho = {
        ...this.atwho,
        cur
      }
    },
    selectByKeyboard (e) {
      const offset = e.keyCode === 38 ? -1 : 1
      const { cur, list } = this.atwho
      const nextCur = this.loop
        ? (cur + offset + list.length) % list.length
        : Math.max(0, Math.min(cur + offset, list.length - 1))
      this.atwho = {
        ...this.atwho,
        cur: nextCur
      }
    },
    atClick () {
    },
    insertHtml (html, r, curItem) {
      r.deleteContents()
      const node = r.endContainer
      const newElement = document.createElement('span')
      // Seems `contentediable=false` should includes spaces,
      // otherwise, caret can't be placed well across them
      newElement.appendChild(document.createTextNode(' '))
      newElement.appendChild(this.htmlToElement(html))
      newElement.appendChild(document.createTextNode(' '))
      newElement.setAttribute('data-at-embedded', curItem.account)
      newElement.setAttribute('class', 'tag')
      newElement.setAttribute('contenteditable', false)
      if (node.nodeType === Node.TEXT_NODE) {
        const cut = r.endOffset
        const secondPart = node.splitText(cut)
        node.parentNode.insertBefore(newElement, secondPart)
        r.setEndBefore(secondPart)
      } else {
        // eslint-disable-next-line no-undef
        const t = document.createTextNode(suffix)
        r.insertNode(newElement)
        r.setEndAfter(newElement)
        r.insertNode(t)
        r.setEndAfter(t)
      }
      r.collapse(false) // 参数在IE下必传
      applyRange(r)
      this.$parent.isBlur = false
      // setTimeout(() => {
      //   this.$emit('insert', curItem)
      // }, 20)
    },

    insertItem () {
      // eslint-disable-next-line no-unused-vars
      const { range, offset, list, cur } = this.atwho
      const { atItems, customsEmbedded } = this
      const r = range.cloneRange()
      const text = range.toString()
      const { at, index } = getAtAndIndex(text, atItems)

      // Leading `@` is automatically dropped as `customsEmbedded=true`
      // You can fully custom the output inside the embedded slot
      const start = customsEmbedded ? index : index + at.length
      r.setStart(r.endContainer, start)
      // hack: 连续两次 可以确保click后 focus回来 range真正生效
      applyRange(r)
      applyRange(r)
      const curItem = list[cur]

      if (customsEmbedded) {
        // `suffix` is ignored as `customsEmbedded=true` has to be
        // wrapped around by spaces
        const html = this.$refs.embeddedItem.firstChild.innerHTML
        console.log(html, r, '1---')
        this.insertHtml(html, r, curItem)
      }
      this.handleInput()
    },
    htmlToElement (html) {
      const template = document.createElement('template')
      html = html.trim() // Never return a text node of whitespace as the result
      template.innerHTML = html
      return template.content.firstChild
    }
  }
}
</script>
